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In Young's double-slit experiment with light of wavelength 600 nm, a…

Question

In Young's double-slit experiment with light of wavelength 600 nm, a thin glass sheet of refractive index 1.5 is introduced over one slit. The central bright fringe shifts to the position previously occupied by the 5th bright fringe. Find the thickness of the glass sheet in micrometres.

✓ Verified answer: 6checked by our engine — not a guess

Step-by-step solution

The extra optical path introduced by the sheet is (n-1)t.

The central fringe shifts by a number of fringes equal to (n-1)t/lambda.

Setting this equal to 5: (n-1)t = 5*lambda, so t = 5*lambda/(n-1) = 5*600e-9/0.5 = 6e-6 m = 6 micrometres.

Final answer6

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